Much damage has recently been caused by the creation and spread of software viruses. As well as the loss and corruption of data, viruses have been responsible for the shutting down of individual computers and even entire networks, leading to a great loss in productivity. The recent “success” of software viruses such as the “Love Letter” virus is due to the proliferation of e-mail as a means of communication between computer users coupled with a lack of knowledge of the potential problems amongst computer users (e.g. users will open e-mail attachments without regard to their origins).
In order to mitigate the potential damage caused by viruses, responsible computer users and network operators make use of anti-virus applications such as the F-Secure™ Anti-Virus product. For network operators, an optimal solution is to install an anti-virus application on individual client computers to scan data created and installed locally (e.g. from a floppy or CD-ROM drive, and an anti-virus application at the e-mail gateway to the network to scan e-mails and their attachments prior to their entry to (and possibly exit from) the network. Anti-virus applications may also be located at other locations. In the case of an anti-virus application located at an e-mail gateway, if a virus is detected in an e-mail and/or e-mail attachment, the e-mail and/or attachment may be disinfected if possible and forwarded to the recipient within the network or, if disinfection is not possible, the e-mail and/or e-mail attachment may be either quarantined or deleted and an appropriate notification sent to the recipient and network administrator.
Anti-virus applications typically make use of a database of virus signatures or fingerprints. Data is scanned by the application for the presence of these signatures. The providers of anti-virus applications are constantly seeking to identify new viruses and to create signatures for these. Following the discovery of a new virus and the generation of a signature for that virus, the damage caused by that virus can be reduced by getting the signature into the field as quickly as possible. The signatures are distributed to anti-virus applications in the field using a number of techniques. Originally, signature updates were provided by posting out floppy disks or CD-ROM disks. However, the most common techniques used today employ Internet based protocols.